To determine: (1) the effect of co-administration of fluconazole and rifabutin, together and alone on the total clearance and hydroxylamine formation clearance of SMX and dapsone in patients with HIV infection. (2) if the degree of inhibition of the formation of the hydroxylamines of SMX and dapsone is altered by induction of cytochrome p450 by rifabutin. (3) if the degree of inhibition of the formation of the hydroxylamines of SMX and dapsone by fluconazole and clarithromycin separately and together is of a magnitude similar to that predicted from in vitro data.